Symptoms
By Mayo Clinic staffInitially, the flu may seem like a common cold with a runny nose, sneezing and sore throat. But colds usually develop slowly, whereas the flu tends to come on suddenly. And although a cold can be a nuisance, you usually feel much worse with the flu.
Common signs and symptoms of the flu include:
- Fever over 100 F (38 C)
- Aching muscles, especially in your back, arms and legs
- Chills and sweats
- Headache
- Dry cough
- Fatigue and weakness
- Nasal congestion
When to see a doctor
If you have flu symptoms and are at risk of complications, see your doctor right away. Taking antiviral drugs within the first 48 hours after you first notice symptoms may reduce the length of your illness and help prevent more-serious problems.
- Seasonal influenza — Questions & answers. Centers for Disease Control and Prevention. http://www.cdc.gov/flu/about/qa/disease.htm. Accessed Nov. 21, 2012.
- Key facts about influenza (flu) & flu vaccine. Centers for Disease Control and Prevention. http://www.cdc.gov/flu/keyfacts.htm. Accessed Nov. 21, 2012.
- Dolin R. Clinical manifestations of seasonal influenza in adults. http://www.uptodate.com/index. Accessed Nov. 21, 2012.
- What you should know about flu antiviral drugs. Centers for Disease Control and Prevention. http://www.cdc.gov/flu/antivirals/whatyoushould.htm. Nov. 21, 2012.
- Dolin R. Epidemiology of influenza. http://www.uptodate.com/index. Accessed Nov. 21, 2012.
- Longo DL, et al. Harrison's Online. 18th ed. New York, N.Y.: The McGraw-Hill Companies; 2012. http://www.accessmedicine.com/resourceTOC.aspx?resourceID=4. Accessed Nov. 21, 2012.
- Influenza antiviral medications: Summary for clinicians. Centers for Disease Control and Prevention. http://www.cdc.gov/flu/professionals/antivirals/summary-clinicians.htm. Accessed Nov. 21, 2012.
- Zachary KC. Treatment of seasonal influenza in adults. http://www.uptodate.com/index. Accessed Nov. 21, 2012.
- What you should know for the 2012-2013 influenza season. Centers for Disease Control and Prevention. http://www.cdc.gov/flu/about/season/flu-season-2012-2013.htm. Accessed Nov. 21, 2012.
- Preventing the flu: Good health habits can help stop germs. Centers for Disease Control and Prevention. http://www.cdc.gov/flu/protect/habits.htm. Accessed Nov. 21, 2012.
- Steckelberg JM (expert opinion). Mayo Clinic, Rochester, Minn. Nov. 30, 2012.
- Jefferson T, et al. Neuraminidase inhibitors for preventing and treating influenza in healthy adults and children. Cochrane Database of Systematic Reviews. http://www.thecochranelibrary.com/view/0/index.html. Accessed Nov. 24, 2012.


Find Mayo Clinic on